October 31, 2005

Rat Brains Rule!

It sounds like the stuff of science fiction: a brain nurtured in a Petri dish learns to pilot a fighter plane as scientists develop a new breed of "living" computer. In ground-breaking experiments in a Florida laboratory, however, that is exactly what is happening. The "brain", grown from 25,000 neural cells extracted from a single rat embryo, has been taught to fly an F-22 jet simulator by scientists at the University of Florida. They hope that the remarkable research into neural computation will help them develop sophisticated hybrid computers, with a thinking biological component.

The brain-in-a-dish is the idea of Thomas DeMarse, a 37-year-old assistant professor of biomedical engineering at the University of Florida. His pioneering work has been praised as a significant insight into one of the universe's most complex devices - the brain - by leading American academics and scientific journals. The 25,000 rat brain neurons were immersed in a specialised liquid suspension to keep them alive and then laid across a grid of 60 electrodes in a small glass dish, measuring only about an inch across. In the most striking experiment, the brain was linked up to the jet simulator. Manipulated via the electrodes and a desktop computer, it was taught to control the flight path, even in mock hurricane-strength winds. "When we first hooked them up, the plane 'crashed' all the time," said Dr DeMarse. "But over time, the neural network slowly adapts as the brain learns to control the pitch and roll of the aircraft. After a while, it produces a nice straight and level trajectory."